KR101709687B1 - Non-planar semiconductor device having channel region with low band-gap cladding layer - Google Patents

Abstract

A non-planar semiconductor device having channel regions with low band gap cladding layers is described. For example, a semiconductor device includes a vertical configuration of a plurality of nanowires disposed on a substrate. Each nanowire includes an inner cladding layer having a first bandgap and an outer cladding layer surrounding the inner cladding layer. The cladding layer has a lower second band gap. The gate stack is disposed on the channel region of each of the nanowires and completely surrounds the channel region of each of the nanowires. The gate stack includes a gate dielectric layer disposed on the cladding layer and surrounding the cladding layer, and a gate electrode disposed on the gate dielectric layer. The source and drain regions are disposed on either side of the channel regions of the nanowires.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a non-flat semiconductor device having a channel region having a low band gap cladding layer,

Embodiments of the present invention are directed to the field of semiconductor devices, and more particularly to the field of non-planar semiconductor devices having channel regions with low band gap cladding layers.

For decades, the scaling of features in integrated circuits has been the driving force for the growing semiconductor industry. Scaling to smaller and smaller features makes it possible to increase the density of functional units on semiconductor chips of limited area. For example, it is possible to include an increased number of memory devices on a chip by reducing transistor size, making it suitable for manufacturing increased capacity products. However, the need for increasing capacity is an issue. The need to optimize the performance of individual devices is becoming increasingly important.

Semiconductor devices formed from III-V material series provide very high carrier mobility in transistor channels due to low effective mass with reduced dopant scattering. Such devices offer high drive current performance and appear promising for future low-power, high-speed logic applications. However, significant improvements are still needed in the field of III-V material-based devices.

Also, in the manufacture of integrated circuit devices, as device dimensions continue to shrink, multi-gate transistors such as tri-gate transistors, or gate-all-around devices such as nanowires become more common . A number of different techniques have been attempted to reduce the junction leakage of such transistors. However, significant improvements are still needed in the field of junction leakage suppression.

1A illustrates a cross-sectional view taken along the channel region of a conventional multi-wire semiconductor device.
FIG. 1B is a graph illustrating a simulation of IOFF parameters for the semiconductor device of FIG. 1A.
Figure 2 illustrates a cross-sectional view taken along the channel region of a multi-wire semiconductor device, in accordance with an embodiment of the present invention.
Figure 3 is a graph 300 illustrating the band structure of a nanowire having a cladding layer, in the form of energy (E) as a function of radius, in accordance with an embodiment of the present invention.
4 illustrates a perspective view of a non-planar semiconductor device having a channel region having a low band gap cladding layer, in accordance with an embodiment of the present invention.
5A illustrates a three-dimensional cross-sectional view of a nanowire-based semiconductor structure having one or more channel regions with a low bandgap cladding layer, in accordance with an embodiment of the present invention.
Figure 5b illustrates a channel cross-sectional view of the nanowire-based semiconductor structure of Figure 5a taken along the a-a 'axis, in accordance with one embodiment of the present invention.
Figure 5c illustrates a spacer cross-sectional view of the nanowire-based semiconductor structure of Figure 5a taken along the b-b 'axis, according to one embodiment of the present invention.
6A-6F illustrate three-dimensional cross-sectional views illustrating various operations in a method of fabricating a CMOS nanowire semiconductor structure, in accordance with an embodiment of the present invention.
Figure 7 illustrates a computing device in accordance with an implementation of the present invention.

Non-planar semiconductor devices having channel regions with low band gap cladding layers are described. In the following description, numerous specific details are set forth such as specific integration and material schemes in order to provide a thorough understanding of embodiments of the present invention. It will be apparent to those skilled in the art that the embodiments of the present invention may be practiced without such specific details. In other instances, well-known features, such as integrated circuit design layouts, are not described in detail in order not to unnecessarily obscure embodiments of the present invention. In addition, it will be appreciated that the various embodiments shown in the figures are illustrative and not necessarily drawn to scale.

One or more embodiments described in the present invention relates to a non-planar semiconductor device having a channel region with a low band gap cladding layer. In one such embodiment, the gate stack of the device completely surrounds the channel region (such as a nanowire or gate-all-around device) and the cladding layer is included all around the channel region. In such other embodiments, the gate stack of the device partially surrounds the channel region only (such as a tri-gate or fin-fet device) and the cladding layer is included only around a portion of the channel region. Such cladding layers may be included to reduce off-state parasitic leakage of an associated semiconductor device, for example a III-V material semiconductor device.

An important consideration in transistor scaling is controlling transistor off-state leakage (Ioff), which affects stand-by power. To address this issue, in the past, a thin-body (e.g., silicon-on-insulator) type structure, a non-planar structure (e.g., a finfet or tri- The semiconductor industry has developed and is considering nanowire devices. The embodiments described in the present invention can utilize bandgap engineering to further improve transistor Ioff. Such improvement may become more important if the semiconductor channel material is replaced with a high mobility material (e.g., a Group III-V material) that typically has a smaller bandgap. The smaller bandgap material is Ioff It can be more sensitive to issues. Nonetheless, bandgap engineering can also be applied to more conventional IV group semiconductors (e.g., Si, SiGe and Ge).

In order to illustrate such concepts and to facilitate comparison with embodiments of the present invention, FIG. 1A illustrates a cross-sectional view taken along the channel region of a conventional multi-wire semiconductor device. 1A, a portion of a semiconductor device 100 includes two nanowire channel regions 102 and 104, for example, III-V material nanowires, such as InGaAs nanowires. A gate stack 106 surrounds the two nanowire channel regions 102 and 104. The gate stack 106 includes a gate dielectric layer adjacent to the two nanowire channel regions 102 and 104 and a gate electrode (not individually shown) adjacent to the gate dielectric layer, for example, a high-k gate A dielectric layer and a metal gate electrode.

1B is a graph illustrating a simulation of IOFF parameters for semiconductor device 100. FIG. Referring to the graph of FIG. 1B, the current in the off-state is distributed approximately evenly across the volume of each nanowire, as opposed to the on-state where current is confined around each nanowire.

In accordance with one embodiment of the present invention, Ioff is reduced by reducing the volume available in one or more nanowires or three-dimensional bodies of a semiconductor device. In such an embodiment, although such an approach may involve fabricating hollow nanowires (e.g., nano-pipes), it may instead use bandgap technology to cause current to flow within the nanowires prevent. Since the former hollow approach may be difficult to implement, the latter approach may be desirable. In such an embodiment, the inner portion of the nanowire or other three-dimensional body has a higher band gap than the outer cladding layer at least partially surrounding the inner portion. In certain embodiments, a low band gap cladding layer is used to constrain the current flow around the nanowires of the three-dimensional body. It will be appreciated that in such embodiments, referred to as the channel region, includes both the inner high band gap material and the outer low band gap cladding layer.

As an example of the cladding approach described above, Figure 2 illustrates a cross-sectional view taken along the channel region of a multi-wire semiconductor device, in accordance with an embodiment of the present invention. Referring to FIG. 2, a portion of semiconductor device 200 includes two internal nanowire channel region portions 202 and 204, e.g., III-V material internal nanowire channel region portions. The two inner nanowire channel region portions 202 and 204 may include a cladding layer 205, for example a III-V material having a lower bandgap than the material of the two inner nanowire channel region portions 202 and 204 And is surrounded by a cladding layer (for example, InGaAs). Thus, as compared to the semiconductor device 100, the semiconductor device 200 is limited to the outside of the nanowire, for example, containing the original III-V channel material as a cladding layer, Gap < / RTI > A gate stack 206 surrounds the cladding layer 205. The gate stack 206 includes a gate dielectric layer adjacent to the cladding layer 205 and a gate electrode (not separately shown) adjacent to the gate dielectric layer, such as a high-k gate dielectric layer and a metal gate electrode. Although two nanowires are depicted in Figure 2, it will be understood that in alternative embodiments, a single nanowire or more than two nanowires may be used.

In one embodiment, the material of inner nanowire channel region portion 202 or 204 has greater bandgap and band offsets than cladding layer 205, so that current flow in the interior region or interior of the channel region . That is, the current flow is limited to the cladding layer 205. Such a cladding layer can be optimized for mobility, effective mass and on-state performance of nanowire (or other three-dimensional body) transistors with reduced off-state issues. On the other hand, the inner portion of the layer may be optimized to reduce the current flow through that portion of the device, for example by increasing its bandgap and band offset relative to the cladding layer.

Figure 3 is a graph 300 illustrating the band structure of a nanowire having a cladding layer, in the form of energy (E) as a function of radius, in accordance with an embodiment of the present invention. Referring to graph 300, the smaller bandgap in the cladding (outer) layer is optimized for transport (on-state), while the inner portion is larger to reduce current flow in the nanowire bulk Band gap.

The semiconductor device 200 (discussed above) or the semiconductor devices 400 and 500 (described below) may be a semiconductor device including a gate, a channel region, and a pair of source / drain regions. In one embodiment, the semiconductor device 200 (or 400 or 500) is such as, but not limited to, a MOS-FET or a MEMS (Microelectromechanical System). In one embodiment, the semiconductor device 200 (or 400 or 500) is a three-dimensional MOS-FET and is either a separation device or a device in a plurality of nested devices. As is recognized for conventional integrated circuits, both N- and P-channel transistors can be fabricated on a single substrate to form a CMOS integrated circuit. Further interconnect interconnects may be fabricated to incorporate such devices into integrated circuits.

As described above, the cladding layer can be used in nanowire devices (see further details with respect to Figures 5A-5C below), other 3D semiconductor devices (e.g., tri-gate or FIN- Devices with protruding channel regions, such as in FETs). In addition, the cladding layer may completely surround the inner channel portion (e.g., FIGS. 5A-5C below) or may only partially surround the inner channel portion (e.g., Lt; / RTI > embodiment).

In a first example, FIG. 4 illustrates a perspective view of a non-planar semiconductor device having a channel region with a low bandgap cladding layer, in accordance with an embodiment of the present invention.

Referring to FIG. 4, semiconductor device 400 includes a hetero-structure 404 disposed over a substrate 402. The hetero-structure 404 includes a bottom barrier layer 428. A three-dimensional III-V material body 406, such as a III-V material body having a channel region 408, is disposed on the bottom barrier layer 428. The three-dimensional body 406 includes an inner region 406A and a cladding layer 406B. The gate stack 418 is disposed to surround at least a portion of the channel region 408. The gate stack 418 includes a gate electrode 424 and a gate dielectric layer 420. The gate stack may further include dielectric spacers 460.

In one embodiment, the gate stack completely surrounds the channel region 408, although not visible in the view of FIG. In that embodiment, the cladding layer 406B may completely surround the inner region 406A at least in the channel region 408. [ However, in other embodiments, the gate stack only partially surrounds the channel region 408. In that embodiment, the cladding layer 406B may also only partially surround the inner region 406A.

Source and drain regions 414/416 may be formed on or on a portion of the three-dimensional body 406 that is not surrounded by the gate stack 418. Also, such regions may also include an upper barrier layer. Also, isolation regions 470 may be included. It will be appreciated that although the depth of the isolation regions 470 is depicted as being somewhat aligned with the bottom of the lower barrier layer 428 in FIG. Also, although depicted as being somewhat aligned with the top of the lower barrier layer 428 in FIG. 4, it will be appreciated that the height of the isolation regions 470 may vary.

The substrate 402 may be composed of a material suitable for semiconductor device fabrication. In one embodiment, the substrate 402 is a bulk substrate comprised of a single crystal of a material that may include, but is not limited to, silicon, germanium, silicon-germanium or III-V compound semiconductor materials. In another embodiment, the substrate 402 comprises a bulk layer having an upper epitaxial layer. In certain embodiments, the bulk layer is comprised of a single crystal of a material that may include, but is not limited to, silicon, germanium, silicon-germanium, III-V compound semiconductor material or quartz, while the upper epitaxial layer Is composed of a single crystal layer that may include, but is not limited to, silicon, germanium, silicon-germanium or III-V compound semiconductor materials. In another embodiment, the substrate 402 comprises an upper epitaxial layer on the intermediate insulating layer present on the lower bulk layer. The upper epitaxial layer may include, but is not limited to, silicon (e.g., to form a silicon-on-insulator) semiconductor substrate), germanium, silicon-germanium or III-V compound semiconductor materials Single crystal layer. The insulator layer is comprised of a material that may include, but is not limited to, silicon dioxide, silicon nitride, or silicon oxynitride. The lower bulk layer is comprised of a single crystal, which may include, but is not limited to, silicon, germanium, silicon-germanium, III-V compound semiconductor materials or quartz. The substrate 402 may further include dopant impurity atoms.

Heterostructure 404 includes a stack of one or more crystalline semiconductor layers, such as a compositional buffer layer (not shown), over which a lower barrier layer 428 is disposed. The composition buffer layer may be composed of a crystalline material suitable for providing a specific lattice structure over which the underlying barrier layer may be formed with negligible dislocations. For example, in accordance with an embodiment of the present invention, by the gradient of the lattice constant, the exposed growth surface of the semiconductor heterostructure 404 can be grown in the lattice structure of the substrate 402, Lt; RTI ID = 0.0 > epitaxial < / RTI > In one embodiment, the composition buffer layer serves to provide a lattice constant that is more suitable for epitaxial growth instead of an incompatible lattice constant of the substrate 402. In one embodiment, the substrate 402 is comprised of monocrystalline silicon and the composition buffer layer is graded with a lower barrier layer comprised of an InAlAs layer of about 1 micron in thickness. In an alternative embodiment, the composition buffer layer is omitted because the lattice constant of the substrate 402 is suitable for growth of the lower barrier layer 428 for the semiconductor device.

The lower barrier layer 428 may be composed of a material suitable for constraining a wave-function in the channel region formed thereon. In accordance with one embodiment of the present invention, the lower barrier layer 428 has a lattice constant that is appropriately matched to the upper lattice constant of the composition buffer layer, for example, Is negligible enough to be neglected. In one embodiment, the lower barrier layer 428 is comprised of a layer of approximately In _{0 .65} Al _{0 .35} As having a thickness of about 10 nanometers. In a particular embodiment, the lower barrier layer 428 is comprised of a layer of approximately In _{0 .65} Al _{0 .35} As, which is used for quantum confinement in an N-type semiconductor device. In another embodiment, the lower barrier layer 428 is comprised of a layer of approximately In _{0 .65} Al _{0 .35} Sb having a thickness of about 10 nanometers. In a particular embodiment, the lower barrier layer 428 is comprised of a layer of approximately In _{0 .65} Al _{0 .35} Sb, which is used for quantum confinement in a P-type semiconductor device.

In one embodiment, the three-dimensional body 406 includes an inner region 406A having a higher band gap than the cladding layer 406B. The choice of combinations of cladding layer 406B / inner region 406A may in principle vary. For example, lattice matched (or nearly lattice matched) pairs can be used in a III-V material scheme, including InGaAs / InP, GaAs / AlGaAs, InSb / AlInSb. Although many embodiments described herein relate to Group III-V material channel regions, other embodiments may include the use of Si / SiGe / Ge. For example, a low bandgap Ge-rich cladding layer can be used with a high bandgap Si-rich inner region. In general, the cladding layer 406B may be composed of a material suitable for propagating the wave function with low resistance. In one embodiment, the cladding layer 406B includes a group III (e.g., boron, aluminum, gallium, or indium) and Group V (e.g., nitrogen, Phosphorus, arsenic, or antimony) elements. In one embodiment, the cladding layer 406B is comprised of InAs or InSb. The cladding layer 406B may have a thickness suitable for propagating a substantial portion of the wave function, for example, to prevent a significant portion of the wave function from entering the inner region 406A have. In one embodiment, the cladding layer 406B has a thickness in the range of about 50-100 A. In the case of a III-V material heterostructure, the inner region 406A may be composed of the same material as the lower barrier layer of the hetero-structure.

If an upper barrier layer is used (not shown), the upper barrier layer may be composed of a material suitable for restraining the wave function in the channel region formed below the III-V material (or other low bandgap material) body . In accordance with one embodiment of the present invention, the top barrier layer has a lattice constant that is appropriately matched to the lattice constant of the cladding layer 406B, e.g., the lattice constants are sufficiently high such that dislocation formation in the top barrier layer is negligible similar. In one embodiment, the top barrier layer is composed of a layer of material such as, but not limited to, N-type InGaAs. For example, the source and drain material regions formed in locations 414 and 416 may be doped III-V material regions, such as a heavily doped structure formed of the same or similar material as the top barrier layer. In other embodiments, source and drain regions are formed in the body 406 at locations 414 and 416. [

Referring again to Figure 4, in one embodiment, the gate electrode 424 of the gate electrode stack 418 is comprised of a metal gate and the gate dielectric layer 420 is comprised of a high-k material. For example, in one embodiment, the gate dielectric layer 420 may include, but is not limited to, hafnium oxide, hafnium oxy-nitride, hafnium silicate, lanthanum oxide, zirconium oxide, zirconium silicate, tantalum oxide, barium strontium titanate, barium titanate, strontium titanate, Such as a yttrium oxide, an aluminum oxide, a lead scandium tantalum oxide, a lead zinc niobate, or a combination thereof. In addition, a portion of the gate dielectric layer 420 may comprise a native oxide layer formed from several layers above the semiconductor body 406. In one embodiment, the gate dielectric layer 420 is comprised of a top high-k portion, and a bottom portion comprised of an oxide of a semiconductor material. In one embodiment, the gate dielectric layer 420 is comprised of a top portion of hafnium oxide and a bottom portion of silicon dioxide or silicon oxynitride.

In one embodiment, the gate electrode 424 can be formed from any suitable material, including, but not limited to, metal nitrides, metal carbides, metal silicides, metal aluminides, hafnium ), Zirconium, titanium, tantalum, aluminum, ruthenium, palladium, platinum, cobalt, nickel, or a conductive metal oxide And the like. In a particular embodiment, the gate electrode 424 is comprised of a non-work function setting fill material formed over the metal work function-setting layer.

In a second example, FIG. 5A illustrates a three-dimensional cross-sectional view of a nanowire-based semiconductor structure having at least one channel region with a low band gap cladding layer, in accordance with an embodiment of the present invention. Figure 5b illustrates a channel cross-sectional view of the nanowire-based semiconductor structure of Figure 5a taken along the a-a 'axis. Figure 5c illustrates a spacer cross-sectional view of the nanowire-based semiconductor structure of Figure 5a taken along the b-b 'axis.

5A, a semiconductor device 500 includes one or more vertically stacked nanowires (504 sets) disposed on a substrate 502. These embodiments target both single wire devices and multiple wire devices. By way of example, three nanowire-based devices with nanowires 504A, 504B, and 504C are shown for illustrative purposes. For ease of illustration, nanowire 504A is used as an example only when only one of the nanowires is described. It will be appreciated that when attributes for one nanowire are described, it is understood that one embodiment based on a plurality of nanowires can have the same properties for each nanowire.

Each nanowire 504 includes a channel region 506 disposed in the nanowire. The channel region 506 has a length L. Referring to FIG. 5B, the channel region also has a perimeter that is orthogonal to the length L. FIG. Referring to both FIGS. 5A and 5B, a gate electrode stack 508 surrounds the entire perimeter of each of the channel regions 506. The gate electrode stack 508 includes a gate electrode with a gate dielectric layer disposed between the channel region 506 and a gate electrode (not shown). The channel region 506 is discontinuous in that it is completely surrounded by the gate electrode stack 508 without any intervening material such as underlying substrate material or overlying channel fabrication material. Thus, in embodiments with a plurality of nanowires 504, the channel regions 506 of the nanowires are also discontinuous with respect to each other, as depicted in FIG. 5B.

In one embodiment, the channel region 506 includes an inner region 506A having a higher band gap than the cladding layer 506B. The choice of combinations of the cladding layer 506B / inner region 506A may in principle vary. For example, lattice matched (or nearly lattice matched) pairs can be used in a III-V material scheme, including InGaAs / InP, GaAs / AlGaAs, InSb / AlInSb. Although many embodiments described herein relate to Group III-V material channel regions, other embodiments may include the use of Si / SiGe / Ge. For example, a low bandgap Ge-rich cladding layer can be used with a high bandgap Si-rich inner region. In general, the cladding layer 506B may be composed of a material suitable for propagating the wave function with low resistance. In one embodiment, the cladding layer 506B is comprised of Group III (e.g., boron, aluminum, gallium, or indium) and Group V (e.g., nitrogen, phosphorus, arsenic, or antimony) elements. In one embodiment, the cladding layer 506B is comprised of InAs or InSb. The cladding layer 506B may have a thickness suitable for propagating a substantial portion of the wave function, for example, a thickness suitable for inhibiting a substantial portion of the wave function from entering the inner region 506A. In one embodiment, the cladding layer 506B has a thickness in the range of about 50-100 A. In the case of a III-V material heterostructure, the inner region 506A may be composed of the same material as the lower barrier layer of the hetero-structure.

In one embodiment, the nanowires 504 can be sized like wires or ribbons (the latter is described below), and can have right-angled or rounded edges. In one embodiment, the nanowires 504 are uniaxially strained nanowires. The uniaxially deformed nanowires or nanowires can be uniaxially deformed using, for example, a tensil strain or a compressive strain for NMOS or PMOS, respectively.

The width and height of each channel region 506 is shown to be approximately the same as in Figure 5b, but need not be. For example, in an alternate embodiment (not shown), the width of the nanowires 504 is significantly greater than the height. In certain embodiments, the width is about 2-10 times greater than the height. Nanowires with such a geometric structure can be referred to as nanoribbons. In another embodiment (also not shown), the nanoribbons are oriented vertically. That is, each of the nanowires 504 has a width and height, and the width is significantly less than the height. In one embodiment, the nanowires 504 may be sized like wires or ribbons and may have right-angled or rounded corners.

Referring again to FIG. 5A, each of the nanowires 504 also includes source and drain regions 510 and 512 disposed on the nanowire on either side of the channel region 506. A pair of contacts 514 is disposed over the source / drain regions 510/512. In a particular embodiment, the pair of contacts 514 surrounds the entire perimeter of each of the source / drain regions 510/512, as depicted in FIG. 5A. That is, in one embodiment, the source / drain regions 510/512 are non-continuous in that they are completely surrounded by the contacts 514 without any intervening material, such as underlying substrate material or overlying channel fabrication materials. to be. Thus, in the embodiment having a plurality of nanowires 504, the source / drain regions 510/512 of the nanowires are also discontinuous with respect to each other.

Referring again to Figure 5A, in one embodiment, the semiconductor device 500 further includes a pair of spacers 516. Spacers 516 are disposed between the gate electrode stack 508 and the pair of contacts 514. As described above, the channel regions and the source / drain regions are fabricated discontinuously, at least in various embodiments. However, not all regions of the nanowires 504 need to be fabricated discontinuously or may not be fabricated discontinuously. For example, referring to FIG. 5C, the nanowires 504A-504C are not discontinuous at the location below the spacers 516. FIG. In one embodiment, the stack of nanowires 504A-504C may be formed from a stack of nanowires, such as germanium interposed between III-V material nanowires, or vice versa, as described below with respect to Figures 6A-6F, And an intervening semiconductor material 580 therebetween. In one embodiment, the lower nanowire 504A is still in contact with a portion of the substrate 502 and contacts, for example, a portion of the insulating layer disposed on the bulk substrate. Thus, in one embodiment, a plurality of vertically stacked nanowire portions beneath one or both spacers are not discontinuous.

Although the above-described device 500 is for a single device, for example an NMOS or PMOS device, it may also be used for NMOS and NMOS devices arranged on the same substrate or on the same substrate, for example as described below with respect to Figures 6A- A CMOS architecture can also be formed to include both PMOS nanowire-based devices.

Referring again to Figures 5A-5C, the substrate 502 may be constructed of a material suitable for semiconductor device fabrication. In one embodiment, the substrate 502 includes a lower bulk substrate comprised of a single crystal of material, which may include, but is not limited to, silicon, germanium, silicon-germanium or III-V compound semiconductor materials. A top insulator layer comprised of a material that may include, but is not limited to, silicon dioxide, silicon nitride, or silicon oxynitride is disposed on the bottom bulk substrate. Thus, the structure 500 may be fabricated from a starting semiconductor-on-insulator substrate. As such, in one embodiment, as depicted in Figures 5A-5C, a plurality of vertically stacked nanowires 504 are disposed on a bulk crystalline substrate over which an intervening dielectric layer is disposed. Alternatively, the structure 500 is formed directly from the bulk substrate and uses local oxidation instead of the above-described top insulator layer to form electrically insulating portions. As such, in another embodiment, a plurality of vertically stacked nanowires 504 are disposed on a bulk crystalline substrate on which intervening dielectric layers are not disposed. In another embodiment, the lower nanowire 504A is separated from the underlying substrate using a top barrier layer having a high band gap, such as a III-V material barrier layer.

In one embodiment, referring again to FIG. 5A, the gate electrode of the gate stack 508 is comprised of a metal gate and the gate dielectric layer is comprised of a high-k material. For example, in one embodiment, the gate dielectric layer may include, but is not limited to, hafnium oxide, hafnium oxy-nitride, hafnium silicate, lanthanum oxide, Zirconium oxide, zirconium silicate, tantalum oxide, barium strontium titanate, barium titanate, strontium titanate, yttrium oxide such as lead oxide, yttrium oxide, aluminum oxide, lead scandium tantalum oxide, lead zinc niobate, or combinations thereof. In addition, a portion of the gate dielectric layer may comprise a native oxide layer formed from several layers above the nanowires 504. In one embodiment, the gate dielectric layer is comprised of a high-k top portion and a bottom portion comprised of an oxide of a semiconductor material. In one embodiment, the gate dielectric layer is comprised of a top portion of hafnium oxide and a bottom portion of silicon dioxide or silicon oxynitride.

In one embodiment, the gate electrode may be formed of a material selected from the group consisting of, but not limited to, metal nitrides, metal carbides, metal silicides, metal aluminides, hafnium, a metal layer such as zirconium, titanium, tantalum, aluminum, ruthenium, palladium, platinum, cobalt, nickel or a conductive metal oxide. . In a particular embodiment, the gate electrode is comprised of a non-work function setting fill material formed over the metal work function-setting layer.

In one embodiment, the spacers 516 are comprised of an insulating dielectric material such as, but not limited to, silicon dioxide, silicon oxynitride, or silicon nitride. Contacts 514, in one embodiment, are made of metal species. The metal species may be pure metals, such as nickel or cobalt, or may be alloys, such as metal-metal alloys or metal-semiconductor alloys (e.g., silicide materials).

Referring again to Figure 5A, each of the nanowires 550 also includes source and drain regions 510/512 disposed on the nanowire or on the nanowire on either side of the channel regions 506 . In one embodiment, the source and drain regions 510/512 are the embedded source and drain regions, e.g., at least a portion of the nanowire is removed and replaced with a source / drain material region. However, in other embodiments, the source and drain regions 510/512 comprise, or at least comprise, a portion of one or more nanowires 504.

Although the above-described device 500 is for a single device, it will be appreciated that a CMOS architecture can also be formed to include both NMOS and PMOS nanowire-based devices on the same substrate or on the same substrate.

Thus, in another aspect, a method of making nanowires having cladding layers is provided. 6A-6F illustrate three-dimensional cross-sections illustrating various operations in a method of fabricating a CMOS nanowire semiconductor structure, in accordance with an embodiment of the present invention.

In one embodiment, a method of making a nanowire semiconductor structure includes forming both a PMOS nanowire-based semiconductor device and an adjacent NMOS nanowire-based semiconductor device. Each device can be fabricated by forming nanowires on a substrate. In a particular embodiment, which ultimately forms two nanowires for each of the NMOS and PMOS nanowire-based semiconductor devices, FIG. 6A shows a substrate 602 (e.g., a bulk substrate having an insulating or barrier layer 602B on it) Lt; / RTI > 602A). ≪ / RTI > A stack of III-V material layer 604 / germanium layer 606 / III-V material layer 608 / germanium layer 610 is disposed on stack 602. Of course, the order of such layers can be reversed.

Referring to FIG. 6B, a stack of III-V material layer 604 / germanium layer 606 / III-V material layer 608 / germanium layer 610, as well as a stack of III- A portion of the upper portion of the insulator or barrier layer 602B is patterned with the fin-like structure 612. [ Thus, in one embodiment, a free surface is formed on either side of each of the III-V material and germanium layers by patterning to provide a fin-like structure 612.

In a particular example illustrating the formation of a three gate structure, Figure 6C illustrates a pin-like structure 612 with three sacrificial gates 614A, 614B and 614C disposed thereon. In one such embodiment, the three sacrificial gates 614A, 614B and 614C are comprised of a sacrificial gate oxide layer 616 and a sacrificial polysilicon gate layer 618, e.g., blanket deposited and patterned by a plasma etch process do.

Following patterning to form the three sacrificial gates 614A, 614B, and 614C, spacers may be formed on the sidewalls of the three sacrificial gates 614A, 614B, and 614C, and the pin- (E. G., End and / or source and drain type doping), covering the three sacrificial gates 614A, 614B, and 614C, and then re- The interlayer dielectric layer can be formed. Then, for the alternate gate or gate-last process, the interlayer dielectric layer may be polished to expose the three sacrificial gates 614A, 614B and 614C. 6D, three sacrificial gates 614A, 614B, and 614C are exposed with spacers 622 and an interlevel dielectric layer 624. As shown in FIG.

The sacrificial gates 614A, 614B, and 614C may then be removed, for example, in a replacement gate or gate-final process flow to expose the channel portions of the fin-like structure 612. 6E, the sacrificial gates 614A, 614B, and 614C are removed to provide the trenches 626 when the NMOS device is fabricated using the pin-like structure 612. As shown in FIG. Leaving portions of germanium layers 606 and 610 exposed by trenches 626 as well as exposed portions of insulating or barrier layer 602B leaving discontinuous portions of III-V material layers 604 and 608 . 6E, the sacrificial gates 614A, 614B, and 614C are removed to provide trenches 628 when fabricating a PMOS device using the pin-like structure 612. [ Leaving portions of the III-V material layers 604 and 608 exposed by the trenches 628 leaving discontinuous portions of the germanium layers 606 and 610.

6E, the germanium nanowire structures 606 and 610 are selectively etched using a wet etch that does not etch the III-V material layers (e. G., ≪ RTI ID = 604 and 608 are selectively etched. 6E, the III-V material nanowire structures 604 and 608 are selectively etched using germanium layers 606 and 610 using a non-etched wet etch. In another embodiment, referring to the left portion of FIG. 6E, As shown in FIG. Thus, the III-V material layers can be removed from the pin-like structure 612 to form germanium channel nanowires, or the germanium layers can be removed from the pin-like structure 612 to form III- Lt; / RTI >

In one embodiment, the discontinuous portions of the III-V material layers 604 and 608 (NMOS) or germanium layers 606 and 610 (PMOS) shown in Figure 6E ultimately cause channel regions in the nanowire- Will be. Thus, in the process steps depicted in Figure 6E, channel engineering or tuning can be performed. For example, in one embodiment, discontinuous portions of the III-V material layers 604 and 608 shown in the left portion of FIG. 6e, or germanium layers 606 and 610 shown in the right portion of FIG. 6e The discontinuous portions are thinned using oxidation and etching processes. Such an etching process may be performed simultaneously with the wires separated by etching the opposing III-V material or germanium layers. Thus, the initial wires formed from the III-V material layers 604 and 608 or the germanium layers 606 and 610 begin to thicken and are thinned in later processing. In addition to or in addition to thinning, a low band gap cladding layer can be formed to surround one or more of the exposed channel regions. The cladding layers may be, for example, those described above, which are cladding layers 205, 406B or 506B.

Following the formation of discrete channel regions as depicted in Figure 6E, high-k gate dielectrics and metal gate processing may be performed and source and drain contacts may be added. In a particular example illustrating the formation of three gate structures on two III-V material nanowires (NMOS) or two germanium nanowires (PMOS), Figure 6F illustrates a cross-sectional view of an NMOS gate stack 630 or a PMOS gate stack RTI ID = 0.0 > 632 < / RTI > The gate stacks may each consist of a high-k gate dielectric layer and an N-type or P-type metal gate electrode layer. Further, FIG. 6F depicts the result of subsequent removal of the interlayer dielectric layer 624 after forming the permanent gate stack. And may form contacts at portions of remaining interlayer dielectric layer 624 in Figure 6E. In one embodiment, at some stages during the removal of the interlayer dielectric layer 624 and during the contact 634 formation process, source and drain engineering may also be performed.

Thus, one or more embodiments described in the present invention target active area configurations with low bandgap outer cladding layers. Although advantages over non-planar and gate-all-around devices have been described above, advantages can also be achieved for planar devices without gate wrap-around features. Accordingly, such configurations may be included to form high mobility material-based transistors such as planar devices, fin or tri-gate based devices, and gate-all-around devices including nanowire-based devices . The formation of materials such as the III-V material layers (or other high mobility, low band gap materials) described in the present invention can be accomplished by any suitable technique, including but not limited to chemical vapor deposition (CVD) or molecular beam epitaxy (MBE) Techniques or other similar processes. ≪ RTI ID = 0.0 >

FIG. 7 illustrates a computing device 700 in accordance with an implementation of the present invention. The computing device 700 receives the board 702. The board 702 may include a number of components including, but not limited to, a processor 704 and at least one communication chip 706. [ The processor 704 is physically and electrically coupled to the board 702. In some implementations, the at least one communication chip 706 is also physically and electrically coupled to the board 702. In further implementations, the communications chip 706 is part of the processor 704.

Depending on the application, computing device 700 may include other components that may or may not be physically and electrically coupled to board 702. These other components include, but are not limited to, volatile memory (e.g., DRAM), non-volatile memory (e.g., ROM), flash memory, graphics processor, digital signal processor, , A touch screen display, a touch screen controller, a battery, an audio codec, a video codec, a power amplifier, a GPS device, a compass, an accelerometer, a gyroscope, a speaker, a camera and a mass storage device (for example, a hard disk drive, ), A digital versatile disk (DVD), etc.).

The communication chip 706 enables wireless communication to and from the computing device 700 to transfer data. The terms "wireless" and its derivatives are intended to encompass all types of communication, such as circuits, devices, systems, methods, techniques, communication channels, etc. that can communicate data by using modulated electromagnetic radiation through a non- Can be used to illustrate. Although not in some embodiments, the term does not suggest that the associated devices do not contain any wires. The communication chip 706 may be any of a variety of communication technologies including but not limited to Wi-Fi (IEEE 802.11 family), WiMAX (IEEE 802.16 family), IEEE 802.20, long term evolution (LTE), Ev-DO, HSPA +, HSDPA +, HSUPA + , Any of a number of wireless standards or protocols including GSM, GPRS, CDMA, TDMA, DECT, Bluetooth, its derivatives as well as any other wireless protocols designated 3G, 4G, 5G and above. The computing device 700 may include a plurality of communication chips 706. For example, the first communication chip 706 may be dedicated to short-range wireless communication such as Wi-Fi and Bluetooth, and the second communication chip 706 may be a GPS, EDGE, GPRS, CDMA, WiMAX, And others. ≪ / RTI >

The processor 704 of the computing device 700 includes an integrated circuit die packaged within the processor 704. In some implementations of the invention, the integrated circuit die of the processor includes one or more devices, such as MOS-FET transistors, constructed in accordance with implementations of the present invention. The term "processor" may refer to any device or portion of a device that processes electronic data from resistors and / or memory and transforms the electronic data into resistors and / or other electronic data that may be stored in memory.

The communication chip 706 also includes an integrated circuit die packaged within the communication chip 706. In accordance with another embodiment of the present invention, an integrated circuit die of a communications chip includes one or more devices, such as MOS-FET transistors, constructed in accordance with an implementation of the present invention.

In further implementations, other components contained within computing device 700 may include integrated circuit dies including one or more devices, such as MOS-FET transistors, constructed in accordance with implementations of the present invention.

In various implementations, the computing device 700 may be a laptop, a netbook, a notebook, an ultrabook, a smartphone, a tablet, a PDA, an ultra mobile PC, a mobile phone, a desktop computer, a server, a printer, a scanner, , A digital camera, a portable music player, or a digital video recorder. In further implementations, computing device 700 may be any other electronic device that processes data.

Accordingly, embodiments of the present invention include non-planar semiconductor devices having channel regions with low band gap cladding layers.

In one embodiment, the semiconductor device comprises a vertical configuration of a plurality of nanowires disposed on a substrate. Each nanowire includes an inner cladding layer having a first bandgap and an outer cladding layer surrounding the inner cladding layer. The cladding layer has a lower second band gap. A gate stack is disposed on each channel region of the nanowires and completely surrounds the channel region. The gate stack includes a gate dielectric layer disposed on the cladding layer and surrounding the cladding layer, and a gate electrode disposed on the gate dielectric layer. Source and drain regions are disposed on either side of the channel regions of the nanowires.

In one embodiment, the cladding layer is comprised of a material suitable for propagating the wave function with low resistance.

In one embodiment, the inner region of each channel region is comprised of a material suitable for substantially preventing current flow from the source regions to the drain regions.

In one embodiment, the material pairs of the cladding layer and the inner region are pairs such as, but not limited to, InGaAs / InP, GaAs / AlGaAs, or InSb / AlInSb.

In one embodiment, the cladding layer is germanium-rich and the interior region is silicon-rich.

In one embodiment, the cladding layer has a thickness suitable to propagate a substantial portion of the wave function and to inhibit a significant portion of the wave function from entering the inner region of each channel region.

In one embodiment, the cladding layer has a thickness in the range of about 50-100 A.

In one embodiment, the source and drain regions are formed in portions of each of the nanowires.

In one embodiment, the source and drain regions of each nanowire are discontinuous with respect to each other, and the semiconductor device further includes a conductive drain contact that surrounds each of the conductive source contact and discontinuous drain regions surrounding each of the discrete source regions do.

In one embodiment, the gate dielectric layer is a high-k gate dielectric layer and the gate electrode is a metal gate electrode.

In one embodiment, a semiconductor device includes a hetero-structure disposed over a substrate and including a three-dimensional semiconductor body having a channel region. The channel region includes an inner region having a first bandgap and an outer cladding layer at least partially surrounding the inner region. The cladding layer has a lower second band gap. The gate stack is disposed over the channel region and at least partially surrounds the channel region. The gate stack includes a gate dielectric layer disposed on the cladding layer, and a gate electrode disposed on the gate dielectric layer. The source and drain regions are disposed on the three-dimensional semiconductor body on either side of the channel region.

In one embodiment, the cladding layer completely surrounds the inner region of the channel region, and the gate stack completely surrounds the channel region.

In one embodiment, the cladding layer only partially surrounds the inner region of the channel region, and the gate stack only partially surrounds the channel region.

In one embodiment, the cladding layer is comprised of a material suitable for propagating the wave function with low resistance.

 In one embodiment, the inner region of the channel region is comprised of a material suitable for substantially preventing current flow from the source region to the drain region.

In one embodiment, the material pairs of the cladding layer and the inner region are pairs such as, but not limited to, InGaAs / InP, GaAs / AlGaAs, or InSb / AlInSb.

In one embodiment, the cladding layer is rich in germanium and the inner region is rich in silicon.

In one embodiment, the cladding layer has a thickness suitable to propagate a substantial portion of the wave function and to inhibit a significant portion of the wave function from entering the inner region of the channel region.

In one embodiment, the cladding layer has a thickness in the range of about 50-100 A.

In one embodiment, the gate dielectric layer is a high-k gate dielectric layer and the gate electrode is a metal gate electrode.

In one embodiment, the semiconductor structure comprises a first semiconductor device. The first semiconductor device includes a first vertical configuration of a plurality of nanowires disposed on a substrate. Each nanowire includes an inner cladding layer having a first bandgap and an outer cladding layer surrounding the inner cladding layer. The cladding layer has a lower second band gap. The first gate stack is disposed on the channel region of each of the nanowires and completely surrounds the channel region. The first gate stack includes a gate dielectric layer disposed on the cladding layer and surrounding the cladding layer, and a gate electrode disposed on the gate dielectric layer. The source and drain regions are disposed on either side of the channel regions of the nanowires of the first vertical configuration of the plurality of nanowires. The semiconductor structure also includes a second semiconductor device. The second semiconductor device also includes a second vertical configuration of a plurality of nanowires disposed on the substrate. A second gate stack is disposed on the channel region of each of the nanowires and completely surrounds the channel region. The second gate stack includes a gate dielectric layer and a gate electrode disposed on the gate dielectric layer. The source and drain regions are disposed on either side of the channel regions of the nanowires of the second vertical configuration of the plurality of nanowires.

In one embodiment, the first semiconductor device is an NMOS device and the second semiconductor device is a PMOS device.

In one embodiment, the cladding layer and the inner region form a III-V material hetero-junction.

In one embodiment, each nanowire of the second semiconductor device includes a second inner region having a first band gap and a second outer cladding layer surrounding the second inner region, wherein the second cladding layer has a lower And has a second band gap.

In one embodiment, the cladding layer and the second cladding layer are each composed of a material suitable for propagating the wave function with low resistance.

In one embodiment, the inner region and the second inner region are each comprised of a material suitable for substantially preventing current flow from each of the source regions to the drain regions.

In one embodiment, the material pairs of the cladding layer and the inner region are pairs such as but not limited to InGaAs / InP, GaAs / AlGaAs or InSb / AlInSb, the second cladding layer is rich in germanium, Is rich in silicon.

In one embodiment, each of the cladding layer and the second cladding layer has a thickness suitable for propagating a substantial portion of the wave function and inhibiting a substantial portion of the wave function from entering the inner region and the second inner region, respectively.

In one embodiment, each of the cladding layer and the second cladding layer has a thickness in the range of about 50-100 A.

In one embodiment, the gate dielectric layer of the first gate stack is a high-k gate dielectric layer, and the gate electrode of the first gate stack is an N-type metal gate electrode.

In one embodiment, the gate dielectric layer of the second gate stack is a high-k gate dielectric layer and the gate electrode of the second gate stack is a P-type metal gate electrode.

Claims (20)

1. A semiconductor device comprising:
A vertical structure of a plurality of nanowires disposed on a substrate, each nanowire being oriented horizontally with respect to the substrate, each nanowire having an inner region having a first band gap and an outer cladding layer surrounding the inner region Wherein the cladding layer has a second bandgap narrower than the first bandgap;
A gate stack disposed on a channel region of each of the nanowires and completely surrounding a channel region of each of the nanowires, the gate stack comprising a gate dielectric layer disposed on the cladding layer and surrounding the cladding layer, A gate electrode disposed on the dielectric layer; And
Source and drain regions disposed on either side of the channel regions of the nanowires
/ RTI >
The source and drain regions of each nanowire being discontinuous with respect to each other, the semiconductor device comprising:
A conductive source contact surrounding each of said discrete source regions; And
The conductive drain contacts surrounding each of the discrete drain regions
≪ / RTI > 2. The semiconductor device of claim 1, wherein the cladding layer comprises a material comprising at least one element selected from the group consisting of Group III and Group V elements for propagating a wave-function. 3. The semiconductor device of claim 2, wherein the inner region of each channel region comprises a material having a bandgap greater than the cladding layer to prevent current flow from the source regions to the drain regions. The semiconductor device of claim 1, wherein the material pairs of the cladding layer and the inner region are selected from the group consisting of InP / InGaAs, GaAs / AlGaAs, and AlInSb / InSb. 2. The semiconductor device of claim 1, wherein the cladding layer has more germanium than the inner region and the inner region has more silicon than the cladding layer. delete 2. The semiconductor device of claim 1, wherein the cladding layer has a thickness in the range of 50-100 A. 2. The semiconductor device of claim 1, wherein the source and drain regions are formed in portions of each of the nanowires. delete The semiconductor device of claim 1, wherein the gate dielectric layer is a high-k gate dielectric layer and the gate electrode is a metal gate electrode. 1. A semiconductor device comprising:
A hetero-structure comprising a three-dimensional semiconductor body disposed on a substrate and having a channel region comprising an inner region having a first band gap and an outer cladding layer at least partially surrounding the inner region, Wherein the hetero-structure comprises a bottom barrier layer disposed below the three-dimensional semiconductor body, the bottom barrier layer having a second bandgap narrower than the one-band gap, ;
A gate stack disposed on the channel region and at least partially surrounding the channel region, the gate stack comprising a gate dielectric layer disposed on the cladding layer and a gate electrode disposed on the gate dielectric layer, Layer surrounds only the inner region of the channel region, the gate stack only partially surrounding the channel region; And
The source and drain regions disposed on the three-dimensional semiconductor body on either side of the channel region
≪ / RTI > delete delete 12. The semiconductor device of claim 11, wherein the material pairs of the cladding layer and the inner region are selected from the group consisting of InP / InGaAs, GaAs / AlGaAs, and AlInSb / InSb. 12. The semiconductor device of claim 11, wherein the cladding layer has more germanium than the inner region and the inner region has more silicon than the cladding layer. delete delete delete delete delete

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